May in Union averages a daily high of 22.7°C with nights around 12.4°C. Expect roughly 11.6 wet days totalling 100.7mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Union is May–June.
Based on NEWARK LIBERTY INTERNATIONAL AIRPORT, NJ US (8.1km), 1995–2024. 30 years of May data.